Yarn crimping apparatus



Oct. 20, 1964 J. ESHUIS YARN CRIMPING APPARATUS Filed NOV. 28, 1962INVENTOR.

JANNES ESHUIS BY 2 w I:

ATTO RN EY United States Patent 3,153,271 YARN CRIMIENG APPARATUSllannes Eshuis, Arnhem, Netherlands, assignor to American Eulraorporation, Erika, Nil a corporation of Delaware Filed Nov. 28, 1962.,Ser. No. 249,631 Claims priority, application Netherlands 13cc. 5, 1%].3 @Clainrs. (ill. 281) This invention relates generally to crimpingcontinuous filament yarns and tow and more particularly to a device foruse in connection with stutter-box crimping apparatus which greatlyfacilitates starting-up of the process.

In general, apparatus for crimping filament yarns by the stutfer boxmethod comprises two feed rollers and a crimping tube. The feed rollersare provided with smooth cylindrical surfaces and the crimping tube isshaped such that it forms a chamber which is closed at one end by partsof these surfaces of the feed rollers. At its opposite end the chamberis open or alternately may be closed by spring-loaded valves or thelike. Also, such apparatus very often has additional means for heating,cooling, moistening, or finishing the yarns to be crimped to improve theperformance thereof.

During normal operation, the yarn is fed to the nip of the feed rollerswhich feed the yarn into the crimping tube against the pressure of ayarn wad. Of course, when the process begins, the crimping tube does notyet contain such a yarn wad and in order to form the yarn into a wad, itis sometimes the practice to insert a counter-pressure rod in the tube.Usually the rod is held by hand. Although it is possible to get theprocess started in this manner, certain disadvantages result. Forexample, in many cases the yarn becomes entangled between the feedrollers and the crimping tube, causing yarn breakage in addition toclogging the apparatus. Such entanglement apparently results because ofa gap between the crimping tube and feed rollers. Although the tube androllers are positioned so that the space inside the crimping tube isclosed at one end, there is still some play between these parts. Thisplay must be maintained for various reasons. Thus, it is necessary forthe rollers to move apart under spring tension in order to allow thepassage of a thick piece of yarn, a crossing of filaments, or a knot.This freedom of movement must not be impeded by the rollers being incontact with the crimping tube. Moreover, the rollers must be able torotate freely relative to the crimping tube, both when the apparatus iscold and when it heats and expands under operating conditions.

Both requirements make it necessary for a narrow slit 0 to be maintainedbetween the circumferential surfaces of the rollers and the crimpingtube. During normal operation, these slits do not cause anydifficulties. The yarn wad is so coherent that filaments are notwithdrawn by the feed rollers and pushed through the slits. Nor is itpossible for the uncrimped yarn to pass through the slits since it isstopped by the yarn wad. However, when the process is first started,there is no yarn wad present to prevent the uncrimped yarn from passingthrough the slits and much of the time the counter-pressure rod does notprevent this from occurring. Under such circumstances, the feed rollerstransport the yarn or filaments through one of the slits, resulting inthe aforementioned yarn breakage and clogging of the apparatus.

Accordingly, it is an object of this invention to provide an apparatusfor crimping yarn not having the inherent disadvantages of knowncrimping devices.

Another object of this invention is to provide a method for preventingyarn breakage and clogging during the starting-up operation ofstuffer-box crimping apparatus.

Still another object of this invention is to provide stufferbox crimpingapparatus in which yarn breakage and clogice ging caused by passage ofthe yarn between the feed rollers and crimping tube is prevented.

A further object is to provide apparatus for preventing passage of yarnthrough the slit formed between the feed rollers and crimping tube ofconventional staffer-box crimping apparatus while minimizing wear of therollers.

These and other objects will become apparent from the following detaileddescription.

In accordance with the present invention, the slit between thecircumferential surfaces of the feed rollers and crimping tube of aconventional stutter-box crimping apparatus is blocked by a resilientdevice during the startingup operation. The device is composed of amaterial softer than the rollers, but sufficiently rigid, so that itwill not bend away or be pushed aside by the rollers. With such adevice, the yarn cannot pass through the slit and thus entanglementaround the rollers is prevented.

An additional advantage is that the slit can be closed on the outside ofthe crimping tube. It might be expected that the yarn in this case wouldstill enter the slit between the circumferential surface of a roller andthe crimping tube. Surprisingly, this in itself does not cause anydifficulties as long as the yarn is prevented from passing through theslit. In accordance with this invention, it has been found that the slitcan be blocked effectively by placing a resilient closing device infront of the slit and on the outside of the crimping tube. Obviously,from a practical point of view, it is better to provide an apparatus inwhich the closing device can be placed on the outside of the crimpingtube rather than one in which the slit must be blocked on the inside ofthe tube.

After the yarn wad has formed, the closing device can be moved away fromthe slit. Because of this, and the fact that the device is made of asofter material than the rollers, wear of the rollers is prevented. Theclosing device is slidably mounted on the outside of the crimping tubeand is movable as far as the circumferential surfaces of the rollers.

Although the closing device may be constructed as a solid jacket andfrom a great variety of materials, it has been found simpler andpreferable to make the device from a textile material such as a woven,knitted or braided fabric. Fabrics of linear polyamide filament yarnshas been found especially suitable. It has even been found satisfactoryto block the slits by means of a piece of multifilament tow, forexample, a piece of polyamide or polyester tow, knotted in a ring aroundthe crimping tube.

For purposes of illustration and not by way of limitation, the followingdetailed description of a preferred embodiment of the invention is giventaken in conjunction with the accompanying drawing, wherein the figureshows a vertical view in section of a crimping apparatus in which theclosing device is positioned as at the start of the operation.

In the figure, a part of the crimping tube 1 is shown in cross sectionin the plane of feed rollers 2 and 3. At the bottom end of crimping tubell, its shape is such that it is almost closed by feed rollers 2 and 3.Feed rollers 2 and 3 are rotated by shafts 4 and 5 in the directionsindicated by the arrows. The rollers are pressed together by a springtension device (not shown), so that yarn 6 is stuffed against yarn wad7. Counter-pressure is exerted on yarn wad 7 by steel balls 8, thenumber of which varies depending upon the pressure required in the yarnwad.

Between crimping tube 1 and rollers 2 and 3 are two slits l0 and 11.With the apparatus of the prior art, yarn 6 can pass through these slitsduring the starting operation. Not until a reasonably thick yarn wad isformed does this risk cease to exist. In the drawing a partly formedyarn wad 7 is shown. Yarn end 12 leaves the wad 7 at the upper sidethereof and passes through the layer of balls 8, after which it emergesfrom the crimping tube 1. In order to prevent the yarn from being pushedthrough slits and 11, a ring 9 of a synthetic material, such as a fabricwoven of polyamide filaments, is movably mounted around the outside ofthe crimping tube. While a polyamide ring is specifically mentioned,other synthetic materials are also very suitable. The underside of thering 9 is so shaped that it fits accurately against the circumferentialsurfaces of rollers 2 and 3.

When the apparatus is started, ring 9 is slid downwardly against thesurfaces of rollers 2 and 3. The yarn 6 is then threaded between therollers 2 and 3, through tube 1, and its free end 12 passed to a windingdevice. Thereafter, rollers 2 and 3 are put into operation. After asufliciently thick wad of yarn has formed, the winding device is placedin operation. While yarn wad 7 is being formed, ring 9 is held inpressure contact with the rollers 2 and 3 either by hand or by means ofa suitable device (not shown). After a sufi'lcient wad is formed, thering 6 is raised somewhat, so that it is no longer in contact withrollers 2 and 3.

From the foregoing, it can readily be seen that the method and apparatusof this invention prevents yarn 6 from passing through slits 10 and 11.The apparatus eliminates yarn breakage and clogging of the apparatus andresults in a stutter-box crimping operation that is more reliable andmay be combined more satisfactorily with other treatments, particularlythose involving the stretching or drawing of synthetic yarns.

Many alterations, modifications and embodiments within the scope of thisinvention will be apparent to those skilled in the art without departingfrom the spirit and scope thereof. It is therefore intended that theinvention only be limited to the extent set forth in the followingclaims.

What is claimed is:

1. In a stutter-box crimping apparatus having feed rollers and acrimping tube positioned directly adjacent thereto whereby slits areformed between said tube and the circumferential surfaces of saidrollers, the improvement comprising a fabric sleeve slidably mountedaround the outer surface of said crimping tube whereby the sleeve may bemoved to a position blocking said slits and preventing yarn from passingtherethrough during start up of the apparatus.

2. In a stuffer box crimping apparatus having feed rollers and acrimping tube positioned directly adjacent thereto whereby slits areformed between said tube and the circumferential surfaces of saidrollers, the improvement comprising a resilient sleeve slidably mountedaround the outer surface of said crimping tube, said sleeve consistingof a material softer than the rollers but sufficiently rigid so that itwill not bend away or be pushed aside by the rollers, whereby the sleevemay be moved to a position blocking said slits thus preventing yarn frompassing therethrough during start up of the apparatus.

3. The apparatus of claim 2 in which the sleeve consists of a piece ofrnulti-filament tow knotted in a ring around the crimping tube.

References Cited in the file of this patent UNITED STATES PATENTS407,391 Ackroyd et al. July 23, 1889 2,152,295 Weinberger Mar. 28, 19392,695,429 Howes et al. Nov. 30, 1954 2,949,659 Heijins et a1 Aug. 23,1960 3,035,313 Naegeli et al May 22, 1962 FOREIGN PATENTS 883,119 GreatBritain Nov. 22, 1961

1. IN A STUFFER-BOX CRIMPING APPARATUS HAVING FEED ROLLERS AND ACRIMPING TUBE POSITIONED DIRECTLY ADJACENT THERETO WHEREBY SLITS AREFORMED BETWEEN SAID TUBE AND THE CIRCUMFERENTIAL SURFACES OF SAIDROLLERS, THE IMPROVEMENT COMPRISING A FABRIC SLEEVE SLIDABLY MOUNTEDAROUNG THE OUTER SURFACE OF SAID CRIMPING TUBE WHEREBY THE SLEEVE MAY BEMOVED TO A POSITION BLOCKING SAID SLITS AND PREVENTING YARN FROM PASSINGTHERETHROUGH DURING START UP OF THE APPARTUS.